What is the best course of action for a patient experiencing nausea for two weeks, considering their age, gender, and past medical history?

Evaluation and Management of Two-Week Nausea

For a patient with nausea lasting two weeks, begin empiric treatment with metoclopramide 10-20 mg orally every 6 hours or prochlorperazine 10 mg orally every 6 hours while simultaneously investigating for underlying causes through targeted history, medication review, and basic laboratory testing. 1

Initial Diagnostic Priorities

Critical History Elements

• Medication review is essential as anticholinergic medications, antidepressants, and opioids commonly cause chronic nausea 1
• Assess timing patterns: morning-predominant nausea suggests anxiety disorders, gastroparesis, or increased intracranial pressure 1
• In women of childbearing age, pregnancy must be ruled out immediately as it is the most common endocrine cause 2
• Document associated symptoms: severe headache or neurologic signs require urgent evaluation for increased intracranial pressure 1

Essential Laboratory Testing

• Obtain a comprehensive metabolic panel to identify life-threatening causes like hypercalcemia, which directly stimulates the chemoreceptor trigger zone 1
• Check thyroid-stimulating hormone levels, as hypothyroidism commonly presents with chronic nausea 1
• Basic laboratory tests should precede advanced imaging in most cases 2

First-Line Pharmacologic Management

Dopamine Antagonists (Primary Agents)

• Metoclopramide 10-20 mg orally every 6 hours serves dual function as both prokinetic and antiemetic, making it ideal for gastroparesis-related nausea 3, 1
• Prochlorperazine 10 mg orally every 6 hours is equally effective as first-line therapy 3, 1
• Haloperidol 0.5-1 mg orally every 6-8 hours for refractory cases 3, 1

Dosing Strategy

• Initiate antiemetics on an as-needed basis initially 4
• If nausea persists, switch to scheduled around-the-clock dosing for one week rather than continuing as-needed administration 4

Management of Persistent Symptoms

Escalation Algorithm

• Add ondansetron (5-HT3 antagonist) to the dopamine antagonist for synergistic effect if symptoms persist on monotherapy 3, 1
• Consider combining metoclopramide with ondansetron specifically, as this combination provides enhanced relief 4
• Add dexamethasone 4-8 mg three to four times daily if central nervous system involvement is suspected 3

Additional Adjunctive Options

• Anticholinergic agents (scopolamine) or antihistamines (meclizine) can be layered into the regimen 3
• Benzodiazepines (lorazepam or alprazolam) if anxiety contributes to symptoms 3
• Cannabinoids (dronabinol or nabilone) for refractory cases, though evidence is limited to chemotherapy-induced nausea 3

Specific Etiologies Requiring Targeted Treatment

Medication-Induced Nausea

• Discontinue unnecessary medications immediately 3
• Check blood levels of digoxin, phenytoin, carbamazepine, and tricyclic antidepressants if applicable 3
• For opioid-induced nausea, initiate opioid rotation or add non-nauseating coanalgesics 3

Gastroparesis

• Metoclopramide is the preferred agent given its prokinetic properties 3, 1
• Treat concurrent gastropathy with proton pump inhibitors 3

Metabolic Causes

• Correct hypercalcemia and treat dehydration promptly 3
• Address any identified thyroid dysfunction 1

Red Flag Symptoms Requiring Urgent Evaluation

• Severe headache or focal neurologic symptoms mandate immediate imaging for increased intracranial pressure 1
• Significant abdominal pain may indicate obstruction or acute abdomen requiring surgical consultation 1
• Severe dehydration or metabolic derangements necessitate hospitalization 2

Common Pitfalls to Avoid

• Do not ignore persistent nausea complaints, as this leads to non-adherence and potential disease progression 4
• Avoid extensive testing in acute nausea (<7 days) without alarm symptoms; most cases are self-limiting viral syndromes 5, 2
• Do not use chronic continuous antiemetic administration without identifying underlying cause, as the drug interaction profile may change 6
• Recognize that nausea symptoms are poor predictors of functional versus pathological illness—investigation is warranted for two-week duration 7

Alternative Routes of Administration

If oral administration is not feasible due to vomiting severity:

• Consider rectal suppositories, subcutaneous infusions, or intravenous administration 3
• Continuous subcutaneous or intravenous infusions of antiemetics may be necessary for intractable symptoms 3